Abstract: Considering the limitation of conventional methods, a new method for slope reliability analysis is proposed combined with the Gaussian process (GP) and importance sampling method (ISM). A small number of learning samples are built by the limit equilibrium method. The implicit performance function is reconstructed by the GP model based on statistical learning. Thus, the implicit performance and its derivatives in slope stability analysis are approximated by the GP model with explicit formulation. An iterative algorithm is presented to improve constantly the reconstructing precision at the important region, which contributes to the failure probability significantly. Then, the importance sampling method is employed to get reliability results of slope. The test results show that the proposed method is feasible and has high accuracy and efficiency.